The present invention relates to a vibratory conveyor capable of fluidizing particulate material and more specifically to a conveyor that allows variations in the degree of fluidization of a particulate material on a vibratory conveyor together with independent variations in the speed and direction of the material on the conveyor.
Shaker or vibratory conveyors are commonly used for transporting particulate material and may be used for drying particulate material. When used for drying, the degree of fluidization of the material is important to allow drying gas to pass through there or circulate around. Such conveyors invariably have troughs or pans, which may or may not be perforated dependent upon their use. In existing perforated trough conveyors used for drying, the degree of fluidization is dependent at least partly on the gas flow and the retention time of the particulate material being conveyed is dependent upon the speed the material moves in the trough together with the length of the trough.
The invention is the owner or co-owner of the following patents related to the present invention:
U.S. Pat. No. 4,548,623 and Canadian Patent No. 1240918 entitled Perforated Trough Conditioning Device
U.S. Pat. No. 5,816,386 entitled Fluidizer Conveyor
Applicant is also the owner of the U.S. Pat. No. 6,035,543, issued, Mar. 14, 2000, and now U.S. Pat. No. 6,035,543.
Fluidizer conveyors have troughs that are vibrated by mechanical, electrical, pneumatic or hydraulic devices. These include hinged rocker arms, eccentrically loaded wheels, pulsating magnets or pneumatic or hydraulic cylinders.
A review of other available designs for fluidizing with vibrations reveals a fixed relationship between the vertical component for fluidization and the horizontal component for material velocity in the conveyor trough. Typical equipment includes eccentrically weighted motors for conveyor troughs, supported by inclined struts or springs which are caused to rapidly reciprocate horizontally. The vertical and horizontal components of the vibration forces are a function of the sine and cosine of the angle of the supporting strut or spring, or the angle of the axis of the eccentric motor.
Eccentrically weighted motors are used on large helical feeders where control of material velocity is the only requirement. Such motors cannot be too large otherwise the vibration forces produced may become destructive. These vibration forces act in a plane of rotation of 360.degree. whereas the useful vertical forces needed are substantially in a single vertical plane. Thus, there are unproductive vibration forces that if excessive cause damage to the structure. Some designs overcome these problems by providing pairs of eccentric weights phased to offset the horizontal forces.